Continuous variable valve duration apparatus and engine provided with the same

ABSTRACT

A continuous variable valve duration apparatus may include a camshaft, a first and second cam portions on which a cam is formed respectively, of which the camshaft is inserted thereto and of which relative phase angles with respect to the camshaft are variable, a first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively, a slider housing in which the first and second inner brackets are rotatably inserted, of which a relative position with respect to the camshaft is variable, and on which a control slot is formed, a cam cap rotatably supporting the first and the second cam portions and to which the slider housing is slidably mounted, a control shaft parallel to the camshaft and on which a control rod is eccentrically formed, an eccentric plate rotatably connected to the control rod and rotatably inserted into the control slot, a separation prevention pin disposed to inhibit the eccentric plate from being separated from the slider housing and a control portion selectively rotating the control shaft so as to controlling a position of the slider housing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2015-0177487, filed on Dec. 11, 2015, the entirecontents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a continuous variable valve durationapparatus and an engine provided with the same.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

An internal combustion engine generates power by burning fuel in acombustion chamber in an air media drawn into the chamber. Intake valvesare operated by a camshaft in order to intake the air, and the air isdrawn into the combustion chamber while the intake valves are open. Inaddition, exhaust valves are operated by the camshaft, and a combustiongas is exhausted from the combustion chamber while the exhaust valvesare open.

Optimal operation of the intake valves and the exhaust valves depends ona rotation speed of the engine. That is, an optimal lift or optimalopening/closing timing of the valves depends on the rotation speed ofthe engine. In order to achieve such optimal valve operation dependingon the rotation speed of the engine, various researches, such asdesigning of a plurality of cams and a continuous variable valve lift(CVVL) that can change valve lift according to engine speed, have beenundertaken.

Also, in order to achieve such an optimal valve operation depending onthe rotation speed of the engine, research has been undertaken on acontinuously variable valve timing (CVVT) apparatus that enablesdifferent valve timing operations depending on the engine speed. Thegeneral CVVT may change valve timing with a fixed valve openingduration.

However, the general CVVL and CVVT are complicated in construction andare expensive in manufacturing cost.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the present disclosureand therefore it may contain information that does not form the priorart that is already known to a person of ordinary skill in the art.

SUMMARY

Various aspects of the present disclosure provide a continuous variablevalve duration apparatus and an engine provided with the same which mayvary opening duration of a valve according to operation conditions of anengine, with a simple construction.

A continuous variable valve duration apparatus according to an exemplaryform of the present disclosure may include: a camshaft; first and secondcam portions on which a cam is formed respectively, the camshaftinserted to the first and second cam portions of which relative phaseangles with respect to the camshaft are variable; first and second innerbrackets transmitting rotation of the camshaft to the first and secondcam portions respectively; a slider housing in which the first andsecond inner brackets are rotatably inserted, of which a relativeposition with respect to the camshaft is variable, and on which acontrol slot is formed; a cam cap rotatably supporting the first and thesecond cam portions, and the slider housing slidably mounted to the camcap; a control shaft which is parallel to the camshaft and on which acontrol rod is eccentrically formed; an eccentric plate rotatablyconnected to the control rod and rotatably inserted into the controlslot; a separation prevention pin configured to inhibit or prevent theeccentric plate from being separated from the slider housing; and acontrol portion selectively rotating the control shaft so as to controla position of the slider housing.

A housing pin insertion hole in which the separation prevention pin isinserted may be formed in the slider housing and an eccentric plate pininsertion hole in which the separation prevention pin is inserted may beformed in the eccentric plate along a circumferential direction thereof.

An eccentric plate hole may be eccentrically formed in the eccentricplate and the control rod may be inserted into the eccentric plate hole.

A cam key may be formed on the first and second cam portionsrespectively, a first and a second sliding holes may be formed in thefirst and second inner brackets respectively, a cam key pin, on which acam key slot where the cam key is slidably inserted therein is formed,may be rotatably inserted into the each first sliding hole, a camshaftpin may be connected to the camshaft, and a slider pin, on which acamshaft pin slot where the camshaft pin is slidably inserted therein isformed, may be rotatably inserted into the each second sliding hole.

The continuous variable valve duration apparatus may further include aslider housing bearing disposed between the slider housing and the firstand the second inner bracket respectively.

The continuous variable valve duration apparatus may further include aspacer disposed within the slider housing to inhibit or preventrotations of the first and second inner brackets from being interrupted.

A cam key may be is formed on the first and second cam portionsrespectively, a first and a second sliding holes may be formed in thefirst and second inner brackets respectively, a cam key pin, on which acam key slot where the cam key is slidably inserted therein is formed,may be rotatably inserted into the each first sliding hole, and a sliderpin may include a pin body and a pin head integrally formed with the pinbody, and wherein the pin body may be slidably inserted into thecamshaft and the pin head may be rotatably inserted into the secondsliding hole.

A camshaft oil hole may be formed in the camshaft along a lengthdirection thereof, a body oil hole communicated with the camshaft oilhole may be formed in the pin body, and an oil groove communicated withthe body oil hole may be formed in the pin head.

A shaft hole to which the control shaft is inserted may be formed in thecam cap.

A cam cap guide for guiding movement of the slider housing may be formedon the cam cap.

A slider housing oil line for supplying oil to the cam cap guide isformed in the slider housing.

The cam may be formed on the first and the second cam portions as apair, a cam cap connecting portion may be formed between the two cams(i.e., the pair cams) of each cam portion (i.e., the first and secondcam portions), and a cam support for rotatably supporting the camconnecting portion may be is formed on the cam cap.

The control portion may include a control motor and a planetary gear setconnected to the control shaft and transmitting rotation of the controlmotor to the control shaft.

The control portion may further include a worm wheel connected to theplanetary gear set, and a worm gear engaged with the worm wheel.

The control portion may further include a control portion housing and ahousing cover connected to the control portion housing, wherein theplanetary gear set, the worm wheel and the worm gear may be disposedwithin the control portion housing.

The control portion may further include a position sensor disposedwithin the control portion housing for detecting rotation of the controlshaft.

An engine according to an exemplary form of the present disclosureincludes: a camshaft; first and second cam portions on which a cam isformed respectively, the camshaft inserted to the first and second camportions of which relative phase angles with respect to the camshaft arevariable; first and second inner brackets transmitting rotation of thecamshaft to the first and second cam portions respectively; a sliderhousing in which the first and second inner brackets are rotatablyinserted, of which a relative position with respect to the camshaft isvariable, and on which a control slot is formed; a cam cap rotatablysupporting the first and the second cam portions and the slider housingslidably mounted to the cam cap; a control shaft which is parallel tothe camshaft and on which a control rod is eccentrically formed; aneccentric plate rotatably connected to the control rod and rotatablyinserted into the control slot; a separation prevention pin configuredto inhibit or prevent the eccentric plate from being separated from theslider housing; and a control portion selectively rotating the controlshaft so as to control a position of the slider housing.

A housing pin insertion hole in which the separation prevention pin isinserted may be formed in the slider housing and an eccentric plate pininsertion hole in which the separation prevention pin is inserted may beformed in the eccentric plate along a circumferential direction thereof.

An eccentric plate hole may be eccentrically formed in the eccentricplate and the control rod may be inserted into the eccentric plate hole.

A cam key may be formed on the first and second cam portionsrespectively, a first and a second sliding holes may be formed in thefirst and second inner brackets respectively, a cam key pin, on which acam key slot where the cam key is slidably inserted therein is formed,may be rotatably inserted into the each first sliding hole, a camshaftpin may be connected to the camshaft, a slider pin, on which a camshaftpin slot where the camshaft pin is slidably inserted therein is formed,may be rotatably inserted into the each second sliding hole, and aslider housing bearing may be disposed between the slider housing andthe first and the second inner brackets respectively.

A cam key may be is formed on the first and second cam portionsrespectively, a first and a second sliding holes may be formed in thefirst and second inner brackets respectively, a cam key pin, on which acam key slot where the cam key is slidably inserted therein is formed,may be rotatably inserted into the each first sliding hole, and a sliderpin may include a pin body and a pin head integrally formed with the pinbody, and wherein the pin body may be slidably inserted into thecamshaft and the pin head may be rotatably inserted into the secondsliding hole.

A camshaft oil hole may be formed in the camshaft along a lengthdirection thereof, a body oil hole communicated with the camshaft oilhole may be formed in the pin body, and an oil groove communicated withthe body oil hole may be formed in the pin head.

The control portion may include a control portion housing, a housingcover connected to the control portion housing, a control motor, a wormgear transmitting rotation of the control motor, a worm wheel disposedwithin the control portion housing and engaged with the worm gear, and aplanetary gear set disposed within the control portion housing andtransmitting rotation of the worm wheel to the control shaft.

The control portion may further include a position sensor disposedwithin the control portion housing for detecting rotation of the controlshaft.

As described above, the continuous variable valve duration apparatusaccording to an exemplary form of the present disclosure may vary anopening duration of a valve according to operation conditions of anengine, with a simple construction.

The exemplary continuous variable valve duration apparatus of thepresent disclosure may be reduced in size and thus the entire height ofa valve train may be reduced.

Since the continuous variable valve duration apparatus may be applied toan existing engine without excessive modification, thus productivity maybe enhance and production cost may be reduced.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a perspective view of an engine provided with a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure;

FIG. 2 is a perspective view of a continuous variable valve durationapparatus according to an exemplary form of the present disclosure;

FIG. 3 is a perspective view of a slider housing of a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure;

FIG. 4 is a cross-sectional view along line IV-IV of FIG. 3;

FIG. 5 to FIG. 7 are exploded perspective views of an exemplarycontinuous variable valve duration apparatus of the present disclosure;

FIG. 8 is a cross-sectional view along line VIII-VIII of FIG. 1;

FIG. 9 is a perspective view of a control portion of a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure;

FIG. 10 is an exploded perspective view of a control portion of acontinuous variable valve duration apparatus according to an exemplaryform of the present disclosure;

FIG. 11 is a table showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure;

FIG. 12 is a graph showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure; and

FIG. 13 is a drawing showing a slider pin of a continuous variable valveduration apparatus according to a modified form of the presentdisclosure.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

In the following detailed description, only certain exemplary forms ofthe present disclosure have been shown and described, simply by way ofillustration.

As those skilled in the art would realize, the described forms may bemodified in various different ways, all without departing from thespirit or scope of the present disclosure

A part irrelevant to the description will be omitted to clearly describethe present disclosure, and the same or similar elements will bedesignated by the same reference numerals throughout the specification.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity.

Throughout the specification and the claims, unless explicitly describedto the contrary, the word “comprise” and variations such as “comprises”or “comprising”, will be understood to imply the inclusion of statedelements but not the exclusion of any other elements.

An exemplary form of the present disclosure will hereinafter bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of an engine provided with a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure, and FIG. 2 is a perspective view of a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure.

FIG. 3 is a perspective view of a slider housing of a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure, and FIG. 4 is a cross-sectional view along lineIV-IV of FIG. 3.

FIG. 5 to FIG. 7 are exploded perspective views of an exemplarycontinuous variable valve duration apparatus of the present disclosure,and FIG. 8 is a cross-sectional view along line VIII-VIII of FIG. 1.

Referring to FIG. 1 to FIG. 6, an engine 10 according to an exemplaryform of the present disclosure includes a cylinder head 10, a camcarrier 12 mounted to the cylinder head 10 and a continuous variablevalve duration apparatus mounted to the cam carrier 12.

The continuous variable valve duration apparatus includes a camshaft 30,a first and second cam portions 70 a and 70 b on which a cam 71 and 72is formed respectively, of which the camshaft 30 is inserted thereto andof which relative phase angles with respect to the camshaft 30 arevariable, a first and second inner brackets 80 and 81 transmittingrotation of the camshaft 30 to the first and second cam portions 70 aand 70 b respectively, a slider housing 90 in which the first and secondinner brackets 80 and 81 are rotatably inserted, of which a relativepositions with respect to the camshaft 30 is variable, and on which acontrol slot 94 is formed, a cam cap 40 rotatably supporting the firstand the second cam portions 70 a and 70 b and to which the sliderhousing 90 is slidably mounted, a control shaft 108 parallel to thecamshaft 30 and on which a control rod 110 is eccentrically formed, aneccentric plate 98 rotatably connected to the control rod 110 androtatably inserted into the control slot 94, a separation prevention pin120 disposed for inhibiting or preventing the eccentric plate 98 frombeing separated from the slider housing 90, and a control portion 100selectively rotating the control shaft 108 so as to controlling aposition of the slider housing 90.

The camshaft 30 may be an intake camshaft or an exhaust camshaft and isrotated by a cam sprocket 48 connected to a crankshaft.

In the drawing, 4 cylinders 211, 212, 213 and 214 are formed to theengine, but it is not limited thereto.

A housing pin insertion hole 122 in which the separation prevention pin120 is inserted is formed to the slider housing 90 and an eccentricplate pin insertion hole 124 in which the separation prevention pin 120is inserted is formed to the eccentric plate 98 along circumferentialdirection thereof.

The eccentric plate pin insertion hole 124 is formed alongcircumferential direction of the eccentric plate 98 and the eccentricplate 98 may be rotated within the control slot 94.

An eccentric plate hole 99 is eccentrically formed to the eccentricplate 98 and the control rod 110 is inserted into the eccentric platehole 99.

When the control shaft 108 rotates, the control rod 110 eccentricallyformed to the control shaft 108 rotates eccentrically, and the eccentricplate 98 rotates relatively within to the control slot 94. Then theslider housing 90 moves upward or downward.

The rotation of the control shaft 108 is changed to the movement upwardor downward of the slider housing 90 through the control rod 110eccentrically formed to the control shaft 108 and the eccentric platehole 99 eccentrically formed to the eccentric plate 98, and thusmovement of the slider housing 90 may be performed smoothly.

And since the separation prevention pin 120 is inserted into the housingpin insertion hole 122 and the eccentric plate pin insertion hole 124,thus the eccentric plate 98 may not be separated from the control slot94.

Two cams 71 and 72 are formed to the first and the second cam portions70 a and 70 b respectively and the cam connecting portion 76 is formedbetween the two cams 71 and 72. A cam support 46 rotatably supports thecam connecting portion 76 and is formed to the cam cap 40.

The cams 71 and 72 rotate to open valves 200.

A cam key 74 is formed to the first and second cam portions 70 a and 70b respectively and a first sliding hole 86 and a second sliding hole 88are formed to the first and second inner brackets 80 and 81respectively.

A cam key pin 82 of which a cam key slot 83 where the cam key 74 isslidably inserted therein is formed thereto and the cam key pin 82 isrotatably inserted into the each first sliding hole 86.

A camshaft hole 32 is formed to the camshaft 30 and a camshaft pin 60 isinserted into the camshaft hole 32 to be connected to the camshaft 30.And a slider pin 84 of which a camshaft pin slot 85 where the camshaftpin 60 is slidably inserted therein is formed thereto and the slider pin84 is rotatably inserted into the each second sliding hole 88.

A slider housing bearing 92 in disposed between each slider housing 90and the first and the second inner brackets 80 and 81 thus relativerotations of each slider housing 90 and the first and the second innerbrackets 80 and 81 may be smoothly performed. In the drawings, theslider housing bearing 92 may be a needle bearing, a ball bearing, aroller bearing and so on may be applied thereto.

A spacer 91 is disposed within the slider housing 90 to inhibit orprevent rotations of the first and second inner brackets 80 and 81 frombeing interrupted.

As shown in FIG. 7, since the slider housing 90 is disposed between thefirst cam portion 70 a and the second cam portion 70 b, engine layoutmay be simplified and one slider housing 90 may control rotational speedof the first cam portion 70 a and the second cam portion 70 bsimultaneously. Thus, the continuous variable valve duration apparatusmay be constructed with simplified and elements number may be reduced.

Also, since elements for controlling the valve duration may be reduced,thus power loss of the engine may be reduced.

A cam cap guide 41 guiding movement of the slider housing 90 is formedto the cam cap 40. A slider housing guide surface 95 is formed to theslider housing 90, and the cam cap guide 41 contacts the slider housingguide surface 95 to guide movement of the slider housing 90. Thus theslider housing 90 may move without oscillation or vibration.

A slider housing oil line 96 for supplying oil to the cam cap guide 41is formed to the slider housing 90 thus the movement of the sliderhousing 90 smoothly performed.

A shaft hole 42 in which the control shaft 108 is inserted is formed tothe cam cap 40 for stably supporting the control shaft 108.

Two cams 71 and 72 are formed to the first and the second cam portions70 a and 70 b respectively, the cam connecting portion 76 is formedbetween the two cams 71 and 72, and a cam support 46 rotatablysupporting the cam connecting portion 76 is formed to the cam cap 40.

The cam cap 40 may guide the movement of the slider housing 90, supportthe rotation of the control shaft 108 and rotatably support the firstand the second cam portions 70 a and 70 b, and may simplify a structureand reduce elements of the continuous duration apparatus.

FIG. 9 is a perspective view of a control portion of a continuousvariable valve duration apparatus according to an exemplary form of thepresent disclosure, and FIG. 10 is an exploded perspective view of acontrol portion of a continuous variable valve duration apparatusaccording to an exemplary form of the present disclosure.

Referring to FIG. 9 and FIG. 10, the control portion 100 includes acontrol motor 106 and a planetary gear set 130 connected to the controlshaft 108 and transmitting rotation of the control motor 106. Theplanetary gear set 130 may connects the control motor 106 and thecontrol shaft 108 and increase gear ratio, thus motor capacity of thecontrol motor 106 may be reduced.

The control portion 100 may further include a worm wheel 104 connectedto the planetary gear set 130 and a worm gear 102 engaged with wormwheel 104. By applying the worm gear 102, the worm wheel 104 and theplanetary gear set 130, gear ratio may be further increased, thus motorcapacity of the control motor 106 may be further reduced.

The control portion 100 may further include a control portion housing150, and a housing cover 152 connected to the control portion housing150. And the planetary gear set 130, the worm wheel 104 and the wormgear 102 are disposed within the control portion housing 150.

Since the planetary gear set 130, the worm gear 102 and the worm wheel104 are disposed within the control portion housing 150, thus enginelayout may be simplified.

A connection shaft 140 on which a planetary gear cage 138 and aplanetary gear shaft 139 are formed is connected with the control shaft108.

The planetary gear set 130 includes a sun gear 132 receiving rotation ofthe control motor 106 through the worm wheel 104, ring gear 134 and aplanetary gear 136 engaged with the sun gear 132 and the ring gear 134.

The ring gear 134 is connected to the housing cover 152, the planetarygear 136 is connected to the planetary gear shaft 139 and the rotationof the control motor 106 is reduced in speed and transmitted to thecontrol shaft 108.

A position sensor 142 disposed within the control portion housing 150for detecting the rotation of the control shaft 108.

The position sensor 142 detects rotations of the connection shaft 140,the sun gear 132 or the worm wheel 104 and outputs corresponding signal.

FIG. 11 is a table showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure, and FIG. 12is a graph showing various operations of an exemplary continuousvariable valve duration apparatus of the present disclosure.

Referring to FIG. 1 to FIG. 12, operations of the exemplary continuousvariable valve duration apparatus will be described.

When rotation centers of the camshaft 30 and the first and second innerbrackets 80 and 81 are coincident, that is, the slider housing 90 ispositioned at an original position as shown in FIG. 11, the cams 71 and72 rotate with the same phase angle of the camshaft 30. That is, thecams 71 and 72 and the camshaft 30 rotate with the same speed.

According to engine operation states, an ECU (engine control unit orelectric control unit) transmits control signals to the control motor106 of the control portion 100 to rotate the control shaft 108. Then,the control rod 110 eccentrically formed to the control shaft 108 isrotated to rotate the eccentric plate 98. The rotation of the eccentricplate 98 induces movement of the slider housing 90 along the cam capguide 41.

That is, the rotation of the control shaft 108 is changed to themovement upward or downward of the slider housing 90 through the controlrod 110 eccentrically formed to the control shaft 108 and the eccentricplate hole 99 eccentrically formed to the eccentric plate 98, and thusmovement of the slider housing 90 may be performed smoothly.

According to the rotation of the control shaft 108, positions of theslider housing 90 and the first and the second inner brackets 80 and 81with respect to a rotation center of the camshaft 30 are changed upwardor downward.

When, the position of the slider housing 90 with respect to the camshaft30 is changed, the relative rotation speed of the cams 71 and 72 withrespect to the rotation speed of the camshaft 30 are changed.

While the camshaft pin 60 is rotated together with the camshaft 30, thecamshaft pin 60 is slidable within the camshaft pin slot 85, the sliderpin 84 is rotatably inserted into the second sliding hole 88, the camkey pin 82 is rotatably inserted into the first sliding hole 82, and thecam key 74 is slidable within the cam key slot 83. Thus the relativerotation speed of the cams 71 and 72 with respect to the rotation speedof the camshaft 30 is changed.

As shown in FIG. 4, while the phase angle of the camshaft 30 isconstantly changed when the relative position of the slider housing 90with respect to the rotation center of the camshaft 30 is changeddownward as ΔH1, as shown in FIG. 11, the rotation speed of the cams 71and 72 is relatively slower than rotation speed of the camshaft 30 near60 to 120 degree, then the rotation speed of the cams 71 and 72 isrelatively faster than rotation speed of the camshaft 30 near 240 to 300degree.

As shown in FIG. 4, while the phase angle of the camshaft 30 isconstantly changed when the relative position of the slider housing 90with respect to the rotation center of the camshaft 30 is changed upwardas ΔH2, as shown in FIG. 11, the rotation speed of the cams 71 and 72 isrelatively faster than rotation speed of the camshaft 30 near 60 to 120degree, then the rotation speed of the cams 71 and 72 is relativelyslower than rotation speed of the camshaft 30 near 240 to 300 degree.

That is, as shown in FIG. 12 valve duration D2 in the case that therelative position of the slider housing 90 is changed to ΔH1 is shorterthan valve duration D1 in the case that the position of the sliderhousing 90 is at the original position.

Also, valve duration D3 in the case that the relative position of theslider housing 90 is changed to ΔH2 is longer than valve duration D1 inthe case that the position of the slider housing 90 is at the originalposition.

In FIG. 12, for better comprehension and ease of description, peakpoints in FIG. 10 are constant, but it is not limited thereto.

According to adjusting contacting positions of the valve 200 and the cam71 and 72, contacting angles of the valve 200 and the cam 71 and 72, aposition of the cam key 74 and so on, valve duration may be enlarged byadvancing opening timing and retarding closing timing of the valve 200.Or, valve duration may be shortened by retarding opening timing andadvancing closing timing of the valve 200.

Also, opening timing of the valve 200 may be constant and closing timingof the valve 200 may be retarded or advanced as requested.

Also, closing timing of the valve 200 may be constant and opening timingof the valve 200 may be retarded or advanced as requested.

FIG. 13 is a drawing showing a slider pin of a continuous variable valveduration apparatus according to a modified form of the presentdisclosure.

In the exemplary form, the camshaft pin and the slider pin aredisconnected, however a slider pin 160 as shown in FIG. 10 includes apin body 162 slidably inserted into the camshaft hole 32 of camshaft 30and a pin head 164 integrally formed with the pin body 162 and rotatablyinserted into the second sliding hole 88.

A camshaft oil hole 34 (referring to FIG. 8) is formed to the camshaft30 along a length direction thereof and a body oil hole 166 communicatedwith the camshaft oil hole 34 is formed to the pin body 162.

And an oil groove 168 communicated with the body oil hole 166 is formedto the pin head 164 through a communicating hole 169.

Since lubricant may be supplied from the camshaft oil hole 34 to the oilgroove 168 through the body oil hole 166 and the communicating hole 169,thus friction between the pin head 164 and the second sliding hole 88may be reduced.

Except the slider pin, operations and structures of the continuousvariable valve duration apparatus according to a modified form of thepresent disclosure are the same of the exemplary form described above,repeated description will be omitted.

As described above, the exemplary continuous variable valve durationapparatus of the present disclosure may perform various valve durationsaccording to operation conditions of an engine.

The exemplary continuous variable valve duration apparatus of thepresent disclosure may be reduced in size and thus the entire height ofa valve train may be reduced.

Particularly, since the motor and so on of the control portion may bemounted outside of the cam carrier thus the entire height of an enginemay be reduced.

Since the continuous variable valve duration apparatus may be applied toan existing engine without excessive modification, thus productivity maybe enhance and production cost may be reduced.

While this present disclosure has been described in connection with whatis presently considered to be practical exemplary forms, it is to beunderstood that the present disclosure is not limited to the disclosedforms. On the contrary, it is intended to cover various modificationsand equivalent arrangements included within the spirit and scope of theappended claims.

<Description of symbols> 1: engine 10: cylinder head 12: cam carrier 30:camshaft 32: camshaft hole 40: cam cap 41: cam cap guide 42: shaft hole46: cam support 47: cam cap cover 60: camshaft pin 70a, 70b: first,second cam portion 71, 72: cam 74: cam key 76: cam connecting portion80: first inner bracket 81: second inner bracket 82: cam key pin 83: camkey slot 84: slider pin 85: camshaft pin slot 86: first sliding hole 88:second sliding hole 90: slider housing 91: spacer 92: slider housingbearing 94: control slot 95: slider housing guide surface 96: sliderhousing oil line 98: eccentric plate 99: eccentric plate hole 100:control portion 102: worm wheel 104: worm gear 106: control motor 108:control shaft 110; control rod 120: separation prevention pin 122:housing pin insertion hole 124: eccentric plate pin insertion hole 130:planetary gear set 132: sun gear 134: ring gear 136: planetary gear 138:planetary gear cage 139: planetary gear shaft 140: connection shaft 142:position sensor 150: control portion housing 152: housing cover 160:slider pin 162: pin body 164: pin head 166: body oil hole 168: oilgroove 169: communicate hole 200: valve 211-214: 1-4 cylinders

What is claimed is:
 1. A continuous variable valve duration apparatuscomprising: a camshaft; first and second cam portions on which a cam isformed respectively, the camshaft inserted to the first and second camportions of which relative phase angles with respect to the camshaft arevariable; first and second inner brackets configured to transmitrotation of the camshaft to the first and second cam portionsrespectively; a slider housing in which the first and second innerbrackets are rotatably inserted, a relative position of the sliderhousing with respect to the camshaft being variable, and a control slotformed on the slider housing; a cam cap configured to rotatably supportthe first and the second cam portions, the slider housing slidablymounted to the cam cap; a control shaft which is parallel to thecamshaft and on which a control rod is eccentrically formed; aneccentric plate rotatably connected to the control rod and rotatablyinserted into the control slot; a separation prevention pin configuredto inhibit the eccentric plate from being separated from the sliderhousing; and a control portion configured to selectively rotate thecontrol shaft so as to control a position of the slider housing.
 2. Thecontinuous variable valve duration apparatus of claim 1, wherein ahousing pin insertion hole in which the separation prevention pin isinserted is formed in the slider housing; and an eccentric plate pininsertion hole in which the separation prevention pin is inserted isformed in the eccentric plate along a circumferential direction thereof.3. The continuous variable valve duration apparatus of claim 1, whereinan eccentric plate hole is eccentrically formed in the eccentric plate;and the control rod is inserted into the eccentric plate hole.
 4. Thecontinuous variable valve duration apparatus of claim 1, wherein a camkey is formed on the first and second cam portions, respectively; firstand a second sliding holes are formed in the first and second innerbrackets, respectively; a cam key pin, on which a cam key slot where thecam key is slidably inserted therein is formed, is rotatably insertedinto the each first sliding hole; a camshaft pin is connected to thecamshaft; and a slider pin, on which a camshaft pin slot where thecamshaft pin is slidably inserted therein is formed, is rotatablyinserted into the each second sliding hole.
 5. The continuous variablevalve duration apparatus of claim 1, further comprising a slider housingbearing disposed between the slider housing and the first and the secondinner brackets, respectively.
 6. The continuous variable valve durationapparatus of claim 1, further comprising a spacer disposed within theslider housing and configured to inhibit rotations of the first andsecond inner brackets from being interrupted.
 7. The continuous variablevalve duration apparatus of claim 1, wherein a cam key is formed on thefirst and second cam portions, respectively; a first and a secondsliding holes are formed in the first and second inner brackets,respectively; a cam key pin, on which a cam key slot where the cam keyis slidably inserted therein is formed, is rotatably inserted into theeach first sliding hole; and a slider pin includes a pin body and a pinhead integrally formed with the pin body, and wherein the pin body isslidably inserted into the camshaft and the pin head is rotatablyinserted into the second sliding hole.
 8. The continuous variable valveduration apparatus of claim 7, wherein a camshaft oil hole is formed inthe camshaft along a length direction thereof; a body oil holecommunicated with the camshaft oil hole is formed in the pin body; andan oil groove communicated with the body oil hole is formed in the pinhead.
 9. The continuous variable valve duration apparatus of claim 1,wherein a shaft hole to which the control shaft is inserted is formed inthe cam cap.
 10. The continuous variable valve duration apparatus ofclaim 1, wherein a cam cap guide configured to guide movement of theslider housing is formed on the cam cap.
 11. The continuous variablevalve duration apparatus of claim 10, wherein a slider housing oil lineconfigured to supply oil to the cam cap guide is formed in the sliderhousing.
 12. The continuous variable valve duration apparatus of claim1, wherein the cam is formed on the first and the second cam portions asa pair; a cam cap connecting portion is formed between the paired camsof each of the first and second cam portions; and a cam supportconfigured to rotatably support the cam connecting portion is formed onthe cam cap.
 13. The continuous variable valve duration apparatus ofclaim 1, wherein the control portion comprises: a control motor; and aplanetary gear set connected to the control shaft and configured totransmit rotation of the control motor to the control shaft.
 14. Thecontinuous variable valve duration apparatus of claim 13, wherein thecontrol portion further comprises: a worm wheel connected to theplanetary gear set; and a worm gear engaged with the worm wheel.
 15. Thecontinuous variable valve duration apparatus of claim 14, wherein thecontrol portion further comprises: a control portion housing; and ahousing cover connected to the control portion housing, wherein theplanetary gear set, the worm wheel and the worm gear are disposed withinthe control portion housing.
 16. The continuous variable valve durationapparatus of claim 15, wherein the control portion further comprises: aposition sensor disposed within the control portion housing andconfigured to detect rotation of the control shaft.
 17. An enginecomprising: a camshaft; first and second cam portions on which a cam isformed respectively, the camshaft being inserted to the first and secondcam portions of which relative phase angles with respect to the camshaftare variable; first and second inner brackets configured to transmitrotation of the camshaft to the first and second cam portionsrespectively; a slider housing in which the first and second innerbrackets are rotatably inserted, a relative position of the sliderhousing with respect to the camshaft being variable, and a control slotformed on the slider housing; a cam cap configured to rotatably supportthe first and the second cam portions, the slider housing slidablymounted to the cam cap; a control shaft which is parallel to thecamshaft and on which a control rod is eccentrically formed; aneccentric plate rotatably connected to the control rod and rotatablyinserted into the control slot; a separation prevention pin configuredto inhibit the eccentric plate from being separated from the sliderhousing; and a control portion configured to selectively rotate thecontrol shaft so as to control a position of the slider housing.
 18. Theengine of claim 17, wherein a housing pin insertion hole in which theseparation prevention pin is inserted is formed in the slider housing;and an eccentric plate pin insertion hole in which the separationprevention pin is inserted is formed in the eccentric plate along acircumferential direction thereof.
 19. The engine of claim 18, wherein acamshaft oil hole is formed in the camshaft along a length directionthereof; a body oil hole communicated with the camshaft oil hole isformed in the pin body; and an oil groove communicated with the body oilhole is formed in the pin head.
 20. The engine of claim 17, wherein aneccentric plate hole is eccentrically formed in the eccentric plate; andthe control rod is inserted into the eccentric plate hole.
 21. Theengine of claim 17, wherein a cam key is formed on the first and secondcam portions, respectively; first and a second sliding holes are formedin the first and second inner brackets, respectively; a cam key pin, onwhich a cam key slot where the cam key is slidably inserted therein isformed, is rotatably inserted into the each first sliding hole; acamshaft pin is connected to the camshaft; a slider pin, on which acamshaft pin slot where the camshaft pin is slidably inserted therein isformed, is rotatably inserted into the each second sliding hole; and aslider housing bearing is disposed between the slider housing and thefirst and the second inner brackets, respectively.
 22. The engine ofclaim 17, wherein a cam key is formed on the first and second camportions, respectively; first and a second sliding holes are formed inthe first and second inner brackets, respectively; a cam key pin, onwhich a cam key slot where the cam key is slidably inserted therein isformed, is rotatably inserted into the each first sliding hole; and aslider pin includes a pin body and a pin head integrally formed with thepin body, and wherein the pin body is slidably inserted into thecamshaft and the pin head is rotatably inserted into the second slidinghole.
 23. The engine of claim 17, wherein the control portion comprises:a control portion housing; a housing cover connected to the controlportion housing; a control motor; a worm gear configured to transmitrotation of the control motor; a worm wheel disposed within the controlportion housing and engaged with the worm gear; and a planetary gear setdisposed within the control portion housing and configured to transmitrotation of the worm wheel to the control shaft.
 24. The engine of claim23, wherein the control portion further comprises: a position sensordisposed within the control portion housing and configured to detectrotation of the control shaft.